This post explains why the Windows 7 USB/DVD Download Tool (WUDT) is unable to copy the install files to the USB drive in some cases. The tool allows you to create a copy of your Windows 7 ISO file on a USB flash drive.

Update: If you have problems Windows 7 USB/DVD Download Tool you can try the free alternative Rufus. The most powerful tool for creating a bootable Windows setup flash drive is WinSetupFromUSB.

You might have heard of the stir that Microsoft's Windows 7 USB/DVD Download Tool (WUDT) caused last year when some Open Source watchmen recognized that the tool contained code that violated the GPL. Microsoft was then "forced" to release WUDT under GPLv2. Considering the upset in the media about this incident, I expected a luxurious tool that comes with lots of customization features. I was somewhat disappointed to discover it does nothing else but copy the contents of a Windows 7 install DVD to a USB stick and make it bootable.

Windows-7-USB-DVD-Download Tool-WUDT

The funny thing is that WUDT even failed to perform this simple task with my no-name USB stick. This message was the only thing that the Open Source tool could do for me:

We were unable to copy your files. Please check your USB device and the selected ISO file and try again.

At least, my cheap stick wasn't the cause because everything worked perfectly when I manually did the job (hopefully without violating any Open Source laws). So, I thought, I would write this post for those who might run into the same problems and think they need to buy another USB stick. After all, this is Microsoft software and there are not many options to integrate bugs in such a simple tool.

Anyway, here is what you have to do. Launch a command prompt with admin rights and run the diskpart tool. Note: Before you run these commands read the warning below!

list disk
select disk #
create partition primary
select partition 1
format quick fs=fat32

The "list disk" command will show you the connected drives and with "select disk", you can choose your USB stick.

WARNING: Be careful to select the right drive or else your day won't have a happy end because if you select the wrong drive you will lose all your data on this drive!

The crucial step here is the "clean" command. It overwrites the MBR and the partition table (thereby, deleting everything on the stick). My guess is that WUDT misses this step and only formats the flash drive. It appears my memory stick had some odd partitions (which is not uncommon). When I tried WUDT again with this prepared stick, the Open Source tool mastered its task without further murmur.

By the way, this is also the reason why you shouldn't use the Windows Disk Management applet to prepare the USB stick. This GUI doesn't offer a clean command.

After you prepare the stick, you have to copy the contents of your Windows 7 DVD to the thumb drive, and you are done. If you only have an ISO file, you can use Virtual CloneDrive to mount the Windows 7 install DVD first.

Instead of formatting the partition with FAT32, you can also use NTFS (like WUDT does), but then you need an extra step to make the drive bootable:

Bootsect.exe /nt60 X:

"X:" is the drive letter of your USB stick. Bootsect.exe can be found on the Windows 7 DVD in the boot folder. However, I can't really recommend using NTFS. My USB stick, at least, appeared to be slower with NTFS.

  1. Peter 12 years ago

    Thanks a lot for this post, worked a treat when my Sandisk Micro Cruzer wouldn’t work with the USB DVD tool, where it had done before.

    I have another USB stick with the same problem so gonna test your solution with that and if it works, you just resurrected an old USB stick for me!


  2. Net Guy 12 years ago

    Thanks a lot. This worked for me.. I no longer get that ugly error!

  3. Waruna 12 years ago

    Thanks Brother. Great.

  4. Glenn Ruel Senorin 12 years ago

    Just like Rene Treffer above. I also got the message do to Avira. Disabling Avira allowed me to use WUDT.

  5. Vincent 12 years ago

    good job~ thank you~

  6. Jeff 12 years ago

    For your information:
    You can also correct that problem with the “HP USB Disk Storage Format Tool 2.2.3”, download here or google it:

    Run it as admin, choose the correct drive and do a quick format.

  7. Andyle 12 years ago

    Thank you, my problem has been resolved, thanks a lot.

  8. mitallast 12 years ago

    Thank you, great!

  9. Szam 12 years ago

    Thanks a lot man, works great!

  10. kwon 12 years ago

    wow thanks man helped me a lot.

  11. linuxeasy 12 years ago

    Hey guys, just format your usb drive with HP USB DISK STORAGE FORMAT TOOL, which can also be found here:

    and format your usb stick by selecting fat32 filesystem (quick format will do, no need to check msdos filesystem stuffs)

    and again run the WUDT, and this time it copies. thanks all.

  12. Andrew 12 years ago

    Thanks very much, this worked for me!

  13. Stephane 12 years ago

    Yes, the clean command did the trick. Thanks a lot.

  14. lukasz 12 years ago

    great! it’s working perfect 🙂

  15. John Andersen 12 years ago

    Hi man

    I consider myself to be an IT prof or atleast somewhat pro 🙂 – I had a hard time getting this to work but with your guide it just worded Flawlessly. Thanks mate

  16. Mr Black 12 years ago

    oh thanks so much for this post. you are the best ever.

  17. adhamsalm 12 years ago

    u r great person ever that problem scared me alot i thught my USB Stick is gone thanx alot brother

  18. A dude 12 years ago

    you saved my life twice with this Tut

    thank you so much Michael Pietroforte

  19. Al Strickler 12 years ago

    This worked perfectly for me. Thanks!

  20. Godsmith 12 years ago

    There are a lot of guides on the net regarding making a thumb drive bootable with or without the download tool, but none explains WHY it works (and doesn’t work) like yours do. Two thumbs up!

  21. kintaro 12 years ago

    I have similar problem, but the solution was to disable antivirus which blocked copy process.

  22. CRDN 12 years ago

    DUDE…………. YOU ROCK!!!!! 😀

  23. Cindy Stokes 11 years ago

    OMG, I love you!!! Thank you!!!

  24. koiloli 11 years ago

    thanks alot…haha, it is copying…

  25. imx4uxx 11 years ago

    You can try HP USB Disk storage format tool.
    I formatted my USB with this tool and then used windows 7 USB DVD download tool and it worked like a charm.

    I had error like can not copy before.

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